Boasting about 5,000 members (as of 2017),[1] the party has not fielded a presidential candidate since its primary financial backer—the gigantic red teat—cut its funding in 1989 for being too hard-line.

The party was founded in 1919, two years after the Russian Bolshevik Revolution of 1917, at the order of the Third International (the Comintern), a Soviet outfit set up to organize communist politics worldwide.[2] The Bolshevik Revolution had the effect of splitting the Socialist Party in the U.S. into three factions, two of which were members of the Comintern; the Comintern now asked these parties to unite. In 1920, the Communist Labor Party merged with some of the Communist Party of America membership to form the United Communist Party. The Comintern then told them more forcefully to unite, and the remaining Communist Party of America members joined the following year. The resulting organization went through a series of names until settling on "Communist Party USA" in 1929. The Party's General Secretary, William Z. Foster, stood three times as US Presidential candidate in the 1920s and 30s, winning a peak of 103,307 votes (0.26% share) in 1932 at the height of the Great Depression.

CPUSA recruited heavily among labor activists as it sought to build a power base within the labor movement. Communists and other leftists came to be respected as dedicated union activists and builders, even among those who disagreed with their politics. They gained popularity among the labor movement as the Great Depression disillusioned and radicalized workers. CPUSA also had a ground-breaking role in race relations within labor unions, which had previously stumbled badly on racial issues. CPUSA's recruitment of black workers and advocacy for their enfranchisement within unions, which had previously viewed them with suspicion as strike-breakers, challenged union leadership to adopt more inclusive approaches towards blacks. The result was more effective union organizing during the 1930s and 40s, and a change in the culture of the labor movement that continued into the postwar era. CPUSA's advocacy for black workers was unprecedented among organizations that were not specifically about blacks, and foretelling of the cross-racial support for the Civil Rights movement of the 1950s and 60s.

As a Soviet-funded[3] party, the CPUSA supported a Stalinist line for many years. Here is a speech Stalin gave where he criticized them. It followed the policy of about-faces in 1928 and 1935, when liberals and other non-communist left-wing groups were first anathematized as "social fascists" and then welcomed back into a "popular front" against fascism. When Stalin began the Great Purge and railroaded nearly a million dissenters to the gallows, the party leader compared Trotskyists to cholera bacteria.

As World War II approached, due to the Molotov-Ribbentrop Pact between Hitler and Stalin, the party staunchly opposed the war and U.S. entry into it, only turning in favor of the war when Hitler attacked the Soviet Union. Prominent gay rights activist Harry Hay was a member of the party in the 1930s and 40s, although the party officially prohibited homosexuals from membership; he was eventually reluctantly expelled in 1951.

The party remained staunchly Stalinist until 1956 when Soviet premier Nikita Khrushchev gave the "Secret Speech" denouncing the excesses of Stalinism. This, plus the Soviet invasion of Hungary in 1956, sent the party into crisis; according to the new party line, it had to expel both Stalinists and liberal-minded reformers. It did so.

Even before the 1956 crisis, the party had been declining under steady assaults from Joseph McCarthy and related figures. In the wake of the 1956 crisis, membership crashed over 90% to only about 5,000 people, many of whom were FBI moles. It was now more of a Soviet foreign-ops apparatus than a political party. In 1959 Gus Hall, a former steelworker who had spent time in jail for electoral fraud and "conspiracy to teach and advocate the overthrow of the U.S. government by force and violence", became leader, a position he would hold until 2000.[4]

Even after McCarthy's reputation was ruined and the attacks slackened off through the 1960s, membership did not fully recover, as the radicals of that generation were drawn more to the New Left and countercultural movements than the Soviet party line.

In the 1968 presidential election, the party's candidate was Charlene Mitchell, the first African-American woman to run for the presidency of the USA. She got 1,077 votes. They continued this tradition in the 1980s with black activist Angela Davis standing twice as vice presidential candidate to four-times presidential failure Gus Hall.

When the CPUSA deviated from the Soviet line by refusing to support Mikhail Gorbachev's programs of glasnost and perestroika, the Soviets, after seventy years of funding the party, stopped that primary source of funding in 1989. This prompted a debate over whether or not the party should continue with its line of Marxism-Leninism; the majority voted to retain it, in consequence of which the social-democratic faction departed. They later returned, took over the party, and led a formal rejection of Marxist-Leninism.

The CPUSA today is still Marxist-Leninist and is still run on old-fashioned "democratic centralist" lines (although that's not usually enforced). It does not usually field candidates, but instead encourages votes for the Democratic Party as the lesser of two evils.[5] CPUSA usually gets accused of being washed-up old white liberals by other leftists, and so most of the youth now go into the DSA or one of the smaller more hardline/culty parties.

In 2014 John Bachtell, a trade unionist and community organiser, took over the leadership from Sam Webb.

In accordance with Karl Marx's policy of supporting "every revolutionary movement against the existing social and political order of things," the CPUSA's program expresses solid opposition to racism, sexism, homophobia, xenophobia, and persecution of religious minorities.

↑Some would think this weird, as the Democratic Party and Republican Party are not the only parties that field candidates; the CPUSA's reasoning, it must be concluded, is that they are the only parties that ever get very many elected.